/**
 * ***************************************************************************** Copyright (c)
 * 2012-2015 Red Hat, Inc. All rights reserved. This program and the accompanying materials are made
 * available under the terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html
 *
 * <p>Contributors: Red Hat, Inc. - initial API and implementation
 * *****************************************************************************
 */
package org.eclipse.che.ide.ext.java.jdt.text.edits;

import java.util.ArrayList;
import java.util.List;
import org.eclipse.che.ide.api.editor.text.BadLocationException;
import org.eclipse.che.ide.ext.java.jdt.text.Document;

/**
 * A move target edit denotes the target of a move operation. Move target edits are only valid
 * inside an edit tree if they have a corresponding source edit. Furthermore a target edit can't
 * can't be a direct or indirect child of its associated source edit. Violating one of two
 * requirements will result in a <code>
 * MalformedTreeException</code> when executing the edit tree.
 *
 * <p>Move target edits can't be used as a parent for other edits. Trying to add an edit to a move
 * target edit results in a <code>
 * MalformedTreeException</code> as well.
 */
public final class MoveTargetEdit extends TextEdit {

  private MoveSourceEdit fSource;

  /**
   * Constructs a new move target edit
   *
   * @param offset the edit's offset
   */
  public MoveTargetEdit(int offset) {
    super(offset, 0);
  }

  /**
   * Constructs an new move target edit
   *
   * @param offset the edit's offset
   * @param source the corresponding source edit
   */
  public MoveTargetEdit(int offset, MoveSourceEdit source) {
    this(offset);
    setSourceEdit(source);
  }

  /* Copy constructor */
  private MoveTargetEdit(MoveTargetEdit other) {
    super(other);
  }

  /**
   * Returns the associated source edit or <code>null</code> if no source edit is associated yet.
   *
   * @return the source edit or <code>null</code>
   */
  public MoveSourceEdit getSourceEdit() {
    return fSource;
  }

  /**
   * Sets the source edit.
   *
   * @param edit the source edit
   * @throws MalformedTreeException is thrown if the target edit is a direct or indirect child of
   *     the source edit
   */
  public void setSourceEdit(MoveSourceEdit edit) {
    if (fSource != edit) {
      fSource = edit;
      fSource.setTargetEdit(this);
      TextEdit parent = getParent();
      while (parent != null) {
        if (parent == fSource)
          throw new MalformedTreeException(
              parent, this, "Source edit must not be the parent of the target."); // $NON-NLS-1$
        parent = parent.getParent();
      }
    }
  }

  /* @see TextEdit#doCopy */
  protected TextEdit doCopy() {
    return new MoveTargetEdit(this);
  }

  /* @see TextEdit#postProcessCopy */
  protected void postProcessCopy(TextEditCopier copier) {
    if (fSource != null) {
      MoveTargetEdit target = (MoveTargetEdit) copier.getCopy(this);
      MoveSourceEdit source = (MoveSourceEdit) copier.getCopy(fSource);
      if (target != null && source != null) target.setSourceEdit(source);
    }
  }

  /* @see TextEdit#accept0 */
  protected void accept0(TextEditVisitor visitor) {
    boolean visitChildren = visitor.visit(this);
    if (visitChildren) {
      acceptChildren(visitor);
    }
  }

  // ---- consistency check ----------------------------------------------------------

  /* @see TextEdit#traverseConsistencyCheck */
  int traverseConsistencyCheck(
      TextEditProcessor processor, Document document, List<List<TextEdit>> sourceEdits) {
    return super.traverseConsistencyCheck(processor, document, sourceEdits) + 1;
  }

  /* @see TextEdit#performConsistencyCheck */
  void performConsistencyCheck(TextEditProcessor processor, Document document)
      throws MalformedTreeException {
    if (fSource == null)
      throw new MalformedTreeException(
          getParent(), this, "No source edit provided."); // $NON-NLS-1$
    if (fSource.getTargetEdit() != this)
      throw new MalformedTreeException(
          getParent(), this, "Source edit has different target edit."); // $NON-NLS-1$
  }

  // ---- document updating ----------------------------------------------------------------

  /* @see TextEdit#performDocumentUpdating */
  int performDocumentUpdating(Document document) throws BadLocationException {
    String source = fSource.getContent();
    document.replace(getOffset(), getLength(), source);
    fDelta = source.length() - getLength();

    MultiTextEdit sourceRoot = fSource.getSourceRoot();
    if (sourceRoot != null) {
      sourceRoot.internalMoveTree(getOffset());
      TextEdit[] sourceChildren = sourceRoot.removeChildren();
      List<TextEdit> children = new ArrayList<TextEdit>(sourceChildren.length);
      for (int i = 0; i < sourceChildren.length; i++) {
        TextEdit child = sourceChildren[i];
        child.internalSetParent(this);
        children.add(child);
      }
      internalSetChildren(children);
    }
    fSource.clearContent();
    return fDelta;
  }

  // ---- region updating --------------------------------------------------------------

  /* @see org.eclipse.text.edits.TextEdit#traversePassThree */
  int traverseRegionUpdating(
      TextEditProcessor processor, Document document, int accumulatedDelta, boolean delete) {
    // the children got already updated / normalized while they got removed
    // from the source edit. So we only have to adjust the offset computed to
    // far.
    if (delete) {
      deleteTree();
    } else {
      internalMoveTree(accumulatedDelta);
    }
    return accumulatedDelta + fDelta;
  }

  boolean deleteChildren() {
    return false;
  }
}
